package jsmc.android.utils;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import jsmc.opendata.nantes.util.NeoLog;

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class DataBaseHelper extends SQLiteOpenHelper{

	private String DB_PATH = null; 

	private String DB_NAME = null; 

	private SQLiteDatabase myDataBase; 

	private final Context myContext;

	/**
	 * Constructor
	 * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
	 * @param context
	 */
	public DataBaseHelper(Context context, String DbPath, String DbName) {

		super(context, DbName, null, 1);
		
		this.DB_NAME = DbName;
		this.DB_PATH = DbPath;
		this.myContext = context;
		
	}	

	/**
	 * Creates a empty database on the system and rewrites it with your own database.
	 * */
	public void createDataBase() throws IOException{

		boolean dbExist = checkDataBase();

		if(!dbExist){

			//By calling this method and empty database will be created into the default system path
			//of your application so we are gonna be able to overwrite that database with our database.
			this.getReadableDatabase();

			try {

				copyDataBase();

			} catch (IOException e) {

				throw new Error("Error copying database");

			}
		}

	}

	/**
	 * Check if the database already exist to avoid re-copying the file each time you open the application.
	 * @return true if it exists, false if it doesn't
	 */
	private boolean checkDataBase(){

		SQLiteDatabase checkDB = null;

		try{
			
			String myPath = DB_PATH + DB_NAME;
			NeoLog.v("DataBaseHelper","checkDataBase: "+myPath);
			
			checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

		}catch(SQLiteException e){

			NeoLog.v("DataBaseHelper","checkDataBase error ");

		}

		if(checkDB != null){

			checkDB.close();

		}

		return checkDB != null ? true : false;
	}

	/**
	 * Copies your database from your local assets-folder to the just created empty database in the
	 * system folder, from where it can be accessed and handled.
	 * This is done by transfering bytestream.
	 * */
	private void copyDataBase() throws IOException{

		//Open your local db as the input stream
		InputStream myInput = myContext.getAssets().open(DB_NAME);

		// Path to the just created empty db
		String outFileName = DB_PATH + DB_NAME;

		//Open the empty db as the output stream
		OutputStream myOutput = new FileOutputStream(outFileName);

		//transfer bytes from the inputfile to the outputfile
		byte[] buffer = new byte[1024];
		int length;
		while ((length = myInput.read(buffer))>0){
			myOutput.write(buffer, 0, length);
		}

		//Close the streams
		myOutput.flush();
		myOutput.close();
		myInput.close();

	}

	public void openDataBase(int DBFlag) throws SQLException{

		//Open the database
		String myPath = DB_PATH + DB_NAME;
		myDataBase = SQLiteDatabase.openDatabase(myPath, null, DBFlag);

	}

	@Override
	public synchronized void close() {

		if(myDataBase != null)
			myDataBase.close();

		super.close();

	}

	@Override
	public void onCreate(SQLiteDatabase db) {

	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

	}

	// Add your public helper methods to access and get content from the database.
	// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
	// to you to create adapters for your views.

}
